Piston sensor with baffle plate

A valve assembly comprising:

• a valve body having an inlet, an outlet, and a valve seat disposed between the inlet and outlet;
• a valve plug movably disposed within a body cavity defined in the valve body, the body cavity being disposed between the inlet and the outlet, the valve plug displaceable along a body axis between a closed position in which a sealing surface of the valve plug sealingly engages a sealing surface of the valve seat and a fully-open position in which the sealing surface of the valve plug is offset from the sealing surface of the valve seat;
• a sensing cavity defined in the valve body or in a bonnet coupled to the valve body, the sensing cavity in fluid communication with the inlet of the valve body such that, when in use, a pressure in the sensing cavity is proportional to a pressure in the inlet;
• a piston cavity defined in the valve body or in the bonnet coupled to the valve body, the piston cavity extending from a first end to a second end along the body axis, the piston cavity being partially defined by a cavity side wall that extends from the first end to the second end of the piston cavity;
• a piston having a piston head disposed within the piston cavity, the piston head having a first surface and a second surface, the piston head sealingly engaging the cavity side wall of the piston cavity, wherein a first working volume is defined by the first surface of the piston head and a portion of the piston cavity extending along the body axis between the first end of the piston cavity and the first surface of the piston head, the piston including a piston stem that extends along a piston axis from a first end to a second end, the first end of the piston stem being coupled to the piston head and the second end of the piston stem being disposed within the body cavity;
• a baffle plate disposed between the sensing cavity and the piston cavity, the baffle plate having a first surface and a second surface, wherein the first surface of the baffle plate defines a portion of the sensing cavity and the second surface of the baffle plate defines a portion of the piston cavity, wherein the baffle plate includes a plurality of baffle apertures extending between the first and second surfaces thereof such that the sensing cavity is in fluid communication with the first working volume of the piston cavity such that pressure in the sensing cavity that is communicated to the first working volume of the piston cavity acts on the first surface of the piston head of the piston to displace the piston towards the valve plug, thereby displacing the sealing surface of the valve plug away from the sealing surface of the valve seat, and wherein the plurality of baffle apertures are adapted to restrict the flow of fluid between the sensing cavity and the first working volume.